The main objective of this research project is to understand the role of mitochondrial RNA polymerase in extranuclear transcription and its possible relationship in prokaryotic RNA polymerase. Mitochondrial RNA polymerase from the Morris hepatoma A3924 will be extensively purified and its properties and subunit structure will be compared with those of the mitochondiral RNA polymerase from liver. Similarly, the properties of the mitochondrial enzyme will be compared with those of different species of nuclear RNA polymerase from the same tissue. These studies will reveal the possible biochemical and/or structural alterations in the mitochondrial RNA polymerase during tumorigenesis and also elucidate any structural relationship of the mitochondiral RNA polymerase to the corresponding nuclear enzymes. Finally, similar comparisons will be made between mitochondrial and prokaryotic RNA polymerase. Since mitochondria are thought to have evolved from parasitic bacteria capable of growth within much larger primitive eukaryotes, the latter studies are likely to throw light on this problem.